Plate shears

ABSTRACT

Plate shears having a frame, lower and upper, reciprocable knives, spaced-apart groups of support members in the track in which the upper knife is movable, a locking device for some of the support members, for holding them with their upper contact surfaces flush with the table of the shears, and control means for unlocking the locking device after the upper knife has reached a predetermined position as it moves along the track.

I United States Patent iii imqi Eduard A. Hannl [56] References Cited v v, l UNITED STATES PATENTS Q f:$' 1,1 1969 2,933,966 4/1960 Dehn 83/157 x iz: 1971 3,260,145 7/1966 Giordano 83/157 X Assignee n "I: LG. 3,492,898 2/1970 Benz 83/157 Zoflng S i rlmd Primary Examiner-F rank T. Yost Priority Nov. 15, 1968 Attorney-Tab T. Thein Alll6l/68 ABSTRACT: Plate shears having a frame, lower and 'upper, 2 6 m F reciprocable knives, spaced-apart groups of support members m m in the track in which the upper knife is movable, a locking U.S.Cl. 83/157, device for some of the support members, for holding them 83/ 165 with their upper contact surfaces flush with the table of the Int. Cl. 826d 7/06 shears, and control means for unlocking the locking device Field of Search 83/157, 81, after the upper knife has reached a predetermined position as 165 it moves along the track.

I I I l I I I I l 7 5 l I 1 I 1' I I I l l j F Patented Aug. 24, 1 971 4 Sheets-Sheet 1 INVENTOR ala/mm, 1714 Patented Aug. 24, 1971 3,600,995

4 Sheets-Sheet 2 I I I I v 1 l l I l I I I INVENTOR Agent Patented Aug. 24, 1971 3,600,995

4 Sheets-Sheet 5 9 9 9 9 m l l 1 H i W l l I i i 1 i INVENTOR Eduard z /'mz BY Zw Aim Patented Aug. 24, 1971 3,600,995

4 Sheets-Sheet 4 I N VEN TOR I dqa d IZ/JWIIL' w BY w IZ PLATE SHEARS The present invention relates to plate shears.

Plate shears are used for cutting plates of unlimited lengths and widths. During the cutting operating the off-cut is pressed by the cutting knife obliquely downwardly, and the disadvantage exists that with longer cuts the off-cut is greatly deformed and considerable twisting could arise. In this way the cut edge is not clean and the forward movement of the plate is made difficult.

It has previously been proposed, therefore, to arrange a resilient abutment in the track of the cutting knife which in the state of rest fits with its support flush to the horizontal plane through the cutting edge of the lower knife and can be displaced from this position into the direction of movement of the cutting knife. In this way a cleaner cut is indeed obtained yet the danger of deformation of the off-cut is not eliminated. Furthermore, the off-cut simply falls downwardly which causes time to be wasted in removing it. I

In order to prevent this plate shears have also been proposed in which a movable cutting knife cooperates with contra-bearings which comprise pistons arranged in cylinders and acted on by a pressure medium. In this a first group of pistons is arranged in the track of the cutting knife and a second group at a distance therefrom, a piston each from the first group being operable with a piston each from the second group in pairs and in serial switching. For the removal of the plates rollers may be provided which are arranged in a plane downwardly inclined from the cutting edge in such a way that each roller lies higher than each piston in its lowest end position.

However, this arrangement has also not proved ideal as the contra-bearings are pressed by the knife below the plate to be cut which can cause danger and deformation particularly with this plates.

According to the invention there is provided plate shears, comprising a frame, a lower knife and an upper knife movable thereagainst and movable along a track, a first group of vertically movable support members, a second group of vertically movable support members spaced from said first group, said groups being arranged in the track of the upper knife, a

locking device for at least each of the support members of the first group by means of which the support members can be held in such a position that their upper contact surfaces are flush with the table of the plate shears, and control means for unlocking each locking device after the upper knife has reached predetermined positions in the course of its movement along its track.

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:

' FIG. Us a schematic side elevation of the plate shears;

FIG. 2 shows a schematic top plan view;

FIG. 3 is a schematic front elevation prior to the cut;

FIG. 4 as FIG. 3 but during the cut; and

FIGS. 5 and 6 show variations of a support organ.

Referring to the drawings, the plate shears consist of a frame 1 which carries a table 2. A-fixed knife 3 is connected to this table 2, and a movable knife 4 with cutting organ 5 is adapted to be displaced, as by pivoting, with respect to the fixed knives. I-Iolddown means 6 servesto press a plate 7 to be cut onto'the table 2 and the cutting edge of the fixed knife.

A first group of support members, for example in the form of pistons 9, and at a distance therefrom a second group of support members in the form of pistons 13 are located below the movable knife 4. The two groups of support members support the plate and prevent deformationthereof.

A number of carriers 16 are also provided which include rotatable rollers 17. The carriers 16 runat right angles to the cut edge and extend downwards between the pistons 9 and 13.

In place of the inclined roller track pivotal arms may be employed which seize the plate after it has been cut and on completion of a pivotal movement bring it out of the range of the plate shears for example onto a stack.

In the position shown in FIG. 1, the pistons 9 and 13 are in a state of rest, the support faces 10 and 14, of the pistons 9 and 13 respectively, being at the same height as the cutting face 8 of the fixed knife. On the other hand in thelower position, shown in dotted lines in FIG. 1, the support faces 10and 14 lie below the rollers 17.

The pistons 9 are arranged in cylinders '12 and the pistons 13 in cylinders 15 in such a manner that by suitable action of pressure medium they can be moved upwardly. For this purpose pipes are attached below the cylinders 12 and 15 through which pressurized oil, for example, is passed.

In the embodiment shown in FIG. 1 the pistons 9 have notches wherein a pawl 20, movable radially with respect to the axis of the piston, engages. The pawl is subject to the action of a spring 21 which presses the pawl against the piston 9 and is connected to one end of a double-arm lever 22 which is rotatable mounted at 23 on the cylinder 12. A roller 24 is mounted on the other end of the lever 22 and the lever is pivoted about 23 via the roller by means of a cam 25.

According to the embodiment shown in FIG. 5 the cylinder 12 receives the pressure medium via a nonretur'n valve 26 so that it is locked in its upper position by the pressure prevailing in the cylinder chamber 27. A valve 28 serves for the unlocking through which the pressure'medium can be reduced. This valve 28 is likewise controlled by a cam 25.

The drive of the cam 25 is coupled wit the drive of the cutting knife 4 in such a manner that the cam completes a full rotation for each cutting cycle of the knife. The shape of the cam isat the same time so chosen that the piston is arrested until shortly before the time when the plate is cut at this place.

FIG. 6 shows another embodiment. As in the embodiment shown in FIG. 1 the piston is provided with a notch wherein a pawl 29 engages. At the same time the upper face of the pawl and the upper surface of the notch are chamfered so that pressure on the support face of the piston causes the pawl to slide out downwardly. To prevent this a hydraulic cylinder 30 with piston 31 is provided whose piston rod is supported against the pawl 29. The cylinder 30 is provided with pressurized oil through a pipe 32.

The modus operandi is as follows:

Supposing that the device is in the state of rest as shown in FIGS. 1 and 3. Now if a plate 7 to be cut is fed into the plate shears, then it rests on the table 2 and the support faces 10 and 14. The movable knife 4 starts to sink and in finally located with its right end (FIG. 3) immediately above the right-hand piston 9. The piston 9 is now released, so that it moves downwardly and the out can begin. As soon as the knife 4 approaches the next piston, the next piston is also released. This continues until the plate is completely cut. The piece cut from the plate 7 finally rests on the rollers 17 and moves away thereon. Then after the plate has rolled away a valve operates and the pistons return upwardly into their state of rest and are again. locked by their associated pawl. The plate shears are now ready to cut a new plate and the whole process is repeated.

In the embodiment shown in FIG. 6 the modus operandi is somewhat different:

After the knife 4 has begun to sink it contacts the plate to be cut in the area of the first piston 9. It now exerts through the plate a pressure on the support face of this piston and continues so to do until the pawl 29 is pressed back against the pressure of the piston 31 and thus the piston is released. As the piston 31 is acted on with the same-pressure as the knife 4, locking of the piston adjusts itself automatically to a thick or thin plate because a thick plate is cut at a higher pressure than a thin plate. The thicker the plate to be cut, the greater the cutting pressure, locking being correspondingly stronger. This embodiment has the advantage that the plate shears do not have to be readjusted when different thicknesses of plate are being cut.

in order to eliminate the friction between the chamfered faces of the pawl and of the piston, rollers or balls may be arranged therebetween.

The downward movement of the pistons 9 and 13 normally a first group of vertically movable support members, a second group of vertically movable support members spaced from said first group, said groups being arranged in the track of the upper knife, a locking device for at least each of the support members of the first group by means of which the support members can be held in such a position that their upper contact surfaces are flush with the table of the plate shears, and

control means for unlocking each locking device after the upper knife has reached predetermined positions in the course of its movement along its track.

2. Plate shears as claimed in claim 1, each locking device comprises a pawl movable at right angles to the axis of the support members, engageable in a suitably shaped notch in the support member, a spring for urging the pawl towards the notch and a lever for withdrawing the pawl from the notch,

3. Plate shears as claimed in claim 2, wherein a cam whose movement is controlled by the upper knife of the plate shears is provided to operate the lever for the withdrawal of the pawl.

4. Plate shears as claimed in claim 1, wherein each locking device'comprises a pawl movable at right angles to the axis of the support member, engageable in a suitably shaped notch in the support member and hydraulic means for urging the pawl towards the notch. 

1. Plate shears comprising a frame, a lower knife and an upper knife movable thereagainst and movable along a track, a first group of vertically movable support members, a second group of vertically movable support members spaced from said first group, said groups being arranged in the track of the upper knife, a locking device for at least each of the support members of the first group by means of which the support members can be held in such a position that their upper contact surfaces are flush with the table of the plate shears, and control means for unlocking each locking device after the upper knife has reached predetermined positions in the course of its movement along its track.
 2. Plate shears as claimed in claim 1, each locking device comprises a pawl movable at right angles to the axis of the support members, engageable in a suitably shaped notch in the support member, a spring for urging the pawl towards the notch and a lever for withdrawing the pawl from the notch.
 3. Plate shears as claimed in claim 2, wherein a cam whose movement is controlled by the upper knife of the plate shears is provided to operate the lever for the withdrawal of the pawl.
 4. Plate shears as claimed in claim 1, wherein each locking device comprises a pawl movable at right angles to the axis of the support member, engageable in a suitably shaped notch in the support member and hydraulic means for urging the pawl towards the notch. 